Allocating more RAM?

[Ed]

I allocated more RAM when I switched OS from Vista to XP but I can't remember how I did it unless it was when I was installing XP.

Is there a way to allocate more RAM without reinstalling my OS?

 

Bad video card drivers!
-----------------------

Minecraft was unable to start because it failed to find an accelerated OpenGL mode.
This can usually be fixed by updating the video card drivers.



--- BEGIN ERROR REPORT 7fe0271 --------
Generated 3/22/12 11:13 PM

Minecraft: Minecraft Beta 1.6.6
OS: Windows XP (x86) version 5.1
Java: 1.6.0_31, Sun Microsystems Inc.
VM: Java HotSpot(TM) Client VM (mixed mode), Sun Microsystems Inc.
LWJGL: 2.4.2
[failed to get system properties (java.lang.NullPointerException)]

org.lwjgl.LWJGLException: Pixel format not accelerated
at org.lwjgl.opengl.WindowsPeerInfo.nChoosePixelForma t(Native Method)
at org.lwjgl.opengl.WindowsPeerInfo.choosePixelFormat (WindowsPeerInfo.java:52)
at org.lwjgl.opengl.WindowsDisplay.createWindow(Windo wsDisplay.java:185)
at org.lwjgl.opengl.Display.createWindow(Display.java :311)
at org.lwjgl.opengl.Display.create(Display.java:856)
at org.lwjgl.opengl.Display.create(Display.java:784)
at org.lwjgl.opengl.Display.create(Display.java:765)
at net.minecraft.client.Minecraft.a(SourceFile:287)
at net.minecraft.client.Minecraft.run(SourceFile:683)
at java.lang.Thread.run(Unknown Source)
--- END ERROR REPORT e951a1fc ----------

I'm running a Dell Inspirion 6400 Laptop with Windows XP & 945Express chipset family. I've downloaded the latest drivers from the Dell website.